A universally-recognised definition of ‘psychosurgery’, and more latterly Neurosurgery for Mental Disorder, has been elusive. Interestingly, definitions used in the last thirty years or so have mirrored contemporary thinking on the aetiology of mental disease. One of the first generally acceptable definitions of psychosurgery was provided by Professor Alan Stone in the Massachusetts Task Force Report on psychosurgery (published in 1975):
“…any procedure which, by direct or indirect access to the brain, removes or destroys or interrupts the continuity of the brain tissue that is histologically normal (i.e. tissue that is normal as seen under a microscope, though its physiological functions for properties might obviously be abnormal) for the purpose of altering behaviour or treating a psychiatric illness.” (Cited in O'Callaghan & Carroll, 1982, page xi)
This definition specifically excluded procedures for intractable pain and epilepsy, adding that such conditions “are clearly demonstrable.” Around the same time (1976) the World Health Organisation defined psychosurgery as “…the selective surgical removal or destruction…of neural pathways…with a view to influencing behaviour”.
A similar description, two years earlier, was:
“selective destruction of areas of the brain for the primary purpose of altering thoughts, emotional reactions, personality characteristics of social response patterns” (Chorover, 1974).
These definitions contain within them the implicit assumption that psychosurgery’s primary purpose was the modification of behaviour by a destructive surgical procedure. It is important to emphasise that such concepts do not reflect modern conceptualisations of the potential role for neurosurgery in the management of severe mental disorder. Moving away from surgically altering behaviour, the Canadian Psychiatric Association defined ‘psychosurgery’ as:
“..brain surgery performed on (i) normal tissues of an individual who does not suffer from physical disease, for the purpose of changing or controlling the emotions or behaviour of such an individual, or on (ii) diseased brain tissue of an individual, if the primary objective of the performance of such surgery is to control, change, or affect any emotional or behavioural disturbance in such an individual.” (Earp, 1979)
A more contemporary definition has been offered by the UK Royal College of Psychiatrists (2000), who defined NMD as:
“A surgical procedure for the destruction of brain tissue for the purposes of alleviating specific mental disorders carried out by a stereotactic or other method capable of making an accurate placement of the lesion”.
This definition focuses on symptom relief being the primary goal of surgery and also reflects the notion that mental disorders have their origins in specific neural substrates of the brain. Further, it makes no assumptions about the functional or anatomical normality of the target tissue. Such a definition, incorporating specific anatomical lesions, is the one in general use today in the UK when referring to NMD, and is the one used in this study.
Chorover, S. L. (1974) Behavioral Surgery. Science, 184, 669-670.
Earp, J. D. (1979) Psychosurgery. The position of the Canadian Psychiatric Association. Canadian Journal of Psychiatry, 24, 353-365.
Freeman, C., Crossley, D. & Eccleston, D. (2000) Neurosurgery for mental disorder. Report from the Neurosurgery Working Group of the Royal College of Psychiatrists. London: Royal College of Psychiatrists.
O'Callaghan, M. A. J. & Carroll, D. (1982) Psychosurgery: A Scientific Analysis. Lancaster: MTP Press.